I think what DVF is saying is wise, as always. The scuffing at the front of the shoe is pretty normal. I often find that the front edge of a new pair of shoes gets to look like yours. On other thing, that DVF refers to about whether or not you saw these problems when you bought them, raises the point about ';checking shoes before you buy them. Having been stung twice on the issue,, I always examine shoes very closely before buying them. Still, its easy to be clever after the event.
There is an issue that sometimes arises from really 'off the shelf shoes'. If one shoe has been on display, lots of people may have had their mitts on them and even dropped them. Shoes displayed in the window can, of course, change colour. I currently have a pair of suede shoes that I did not cover up properly. One was exposed to sun. I now have a pair that are slightly different colours.